spoken language - Does using the characters です at the end of a sentence make almost everything(depending on the sentence) sound polite?

For example if i say something like,"あなたはやさしい人です”。

Versus if I say,"あなたはやさしい人".

Is the second sentence (stated above) grammatically correct or does there "need" to be a particle at the end of my sentence?

I appreciate all the help I can get from you wonderful people.

Please give me your knowledge and help me better educate my self.

~A man seeking to improve himself

Answer

There are actually three sentences worth discussing

(1) あなたはやさしい人です

(2) あなたはやさしい人だ

(3) あなたはやさしい人

For each sentence, we should consider three dimensions: grammaticality, softness, and politeness.

(1) is soft (doesn't sound too direct), polite (shows respect for addressee).
(2) is rough (sounds like a point's trying to be made), not polite (doesn't show respect for addressee).
(3) is soft (doesn't sound too direct), not polite (doesn't show respect for addressee).

All three are grammatical.

(Note: "Not polite" doesn't necessarily mean "rude". There is no need to use the polite form with your friends, close family, or people much younger than you, for example -- in these cases the polite form would be overly distant or odd.)

(Note 2: It's probably worth pointing out that the presence of あなた makes all of these sentences sound a little jarring.)